JPH0447717B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermochromic material that reversibly develops and discolors at a predetermined temperature. Previously, the applicant has proposed (a) electron-donating color-forming organic compounds, (b) phenol compounds, and (c) alcohols, esters, ketones, ethers, acid amides,
Thermochromic material consisting of three components selected from carboxylic acids and sulfur compounds
44706, 44707, 44709, 44908, Japanese Patent Publication 1973-
105554, 51-31682, 54-58727, etc.), but the present invention proposes a component that determines the color change temperature of these thermochromic materials and controls the sensitivity of color change.
This further increases the freedom of choice regarding (c). The thermochromic material of the present invention includes (a) an electron-donating color-forming organic compound, (b) a compound having a phenolic hydroxyl group and its metal salt, an aromatic carboxylic acid, and a C2-C5 fat as essential components. Compounds selected from group carboxylic acids and their metal salts, acidic phosphoric acid esters and their metal salts, 1,2,3-triazoles and their derivatives, halohydrins having 2 to 5 carbon atoms and their derivatives, and (iii) nitrile compounds. It consists of a composition containing. The electron-donating color-forming organic compound of component (a) is diarylphthalides, polyarylcarbinols,
These are so-called leuco dyes such as leucouramines, acylouramines, arylauramines, rhodamine B lactams, indolines, spiropyrans, and fluorans. Examples of these compounds are shown below. Crystal violet lactone, malachite green lactone, Michler hydrol, crystal violet carbinol, malachite green carbinol, N-(2,3-dichlorophenyl)leucoohamine, N-benzoyluramine, rhodamine B lactam, N- Acetyl auramine, N-phenyl auramine, 2-(phenyliminoethylidene)-3,3-dimethylindoline, N-3,3-trimethylindolinobenzospiropyran, 8-methoxy-N-3,3-trimethyl Indolinobenzospiropyran, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-6-benzyloxyfluorane, 1,2-benz-6-diethylaminofluorane , 3,6-di-P-toluidino-4,
5-dimethylfluorane-phenylhydrazide-
lactam, 3-amino-5-methylfluorane,
2-Methyl-3-amino-6-methyl-7-methylfluorane, 2,3-butylene-6-di-n-
Butylaminofluorane, 3-diethylamino-
7-anilinofluorane, 3-diethylamino-
7-(para-toluidino)-fluorane, 7-acetamino-3-diethylaminofluorane, 2-bromo-6-cyclohexylaminofluorane,
Examples include 2,7-dichloro-3-methyl-6-n-butylaminofluorane. Next, component (b) will be described. As a compound having a phenolic hydroxyl group,
There are monophenols and polyphenols,
Furthermore, as a substituent, an alkyl group, an aryl group,
Examples include acyl groups, alkoxycarbonyl groups, and halogens. Examples of these compounds are shown below. Tertiary-butylphenol, nonylphenol, dodecylphenol, styrene tate phenol, 2,2-methylenebis-(4-methyl-6-tertiary-butylphenol), α-
Naphthol, β-naphthol, hydroquinone monomethyl ether, guaiacol, eugenol, P-chlorophenol, P-bromophenol, 0-chlorophenol, 0-bromophenol, 0-phenylphenol, P-phenylphenol, P-(P -chlorophenyl)-phenol, 0-(0-chlorophenyl)-phenol, P
-Methyl oxybenzoate, ethyl P-oxybenzoate, propyl P-oxybenzoate, butyl P-oxybenzoate, octyl P-oxybenzoate,
Dodecyl P-oxybenzoate, 3-isopropylcatechol, P-tert-butylcatechol, 4,4-methylenediphenol, 4,4-thio-bis-(6-tert-butyl-3-methylphenol) ), 1,1-bis(4-hydroxyphenyl)-cyclohexane, 4,4-butylidene-bis-(6-tert-butyl-3-methylphenol), bisphenol A, bisphenol S, 1, 2,-Dioxynaphthalene, 2,3
-Dioxynaphthalene, chlorcatechol, promocatechol, 2,4-dihydroxybenzophenone, phenolphthalein, 0-cresolphthalein, methyl protocatechuate, ethyl protocatechuate, propyl protocatechuate, protocatechuate Octyl euate, dodecyl protocatechuate, 2,4,6-trioxymethylbenzene, 2,3,4-trioxyethylbenzene, ethyl gallate, propyl gallate, butyl gallate, hexyl gallate, octyl gallate , dodecyl gallate, cetyl gallate, stearyl gallate, 2,3,5-trioxynaphthalene, tannic acid, phenolic resin, and the like. Examples of metal salts of compounds having a phenolic hydroxyl group include sodium, potassium, lithium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, There are metal salts of metals such as lead and molybdenum. Examples of aromatic carboxylic acids and aliphatic carboxylic acids having 2 to 5 carbon atoms include maleic acid, fumaric acid, benzoic acid, gallic acid, toluic acid, and P-tertiary acid.
Butylbenzoic acid, chlorobenzoic acid, brobenzoic acid, ethoxybenzoic acid, naphthoic acid, phthalic acid,
naphthalene dicarboxylic acid, acetic acid, propionic acid,
Examples include butyric acid and valeric acid. Examples of carboxylic acid metal salts include metal salts of monocarboxylic acids to polycarboxylic acids. Examples of these compounds are shown below. Acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, valmitic acid, stearic acid, isostearic acid, behenic acid, crotonic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid monochloroacetic acid , monobromoacetic acid, monofluoracetic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, ricinoleic acid, 12-hydroxystearic acid, lactic acid, pyruvic acid, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, malic acid, tartaric acid , citrusic acid, maleic acid, fumaric acid, naphthenic acid, benzoic acid, toluic acid, phenylacetic acid, P-tert-butylbenzoic acid, cinnamic acid,
Chlorbenzoic acid, bromobenzoic acid, ethoxybenzoic acid, mandelic acid, protocatechuic acid, vanillic acid, resorcinic acid, dioxybenzoic acid, dioxychlorobenzoic acid, gallic acid, naphthoic acid, hydroxynaphthoic acid, phthalic acid, monophthalic acid Sodium, potassium, lithium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, such as ethyl ester, naphthalene dicarboxylic acid, naphthalene dicarboxylic acid monomethyl ester, trimellitic acid, pyromellitic acid, etc.
There are metal salts of metals such as lead and molybdenum. Examples of the acidic phosphate ester compound include ester groups such as alkyl groups, branched alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, aryl groups, and derivatives thereof. Acidic phosphoric acid ester compounds include monoesters and diesters, and may also be mixtures thereof. In the following compounds, the mixture of monoester and diester is called acid phosphate. Examples of acidic phosphoric acid ester compounds are shown below. Methyl acid phosphate, ethyl acid phosphate, n-propyl acid phosphate, n-butyl acid phosphate, 2-ethylhexyl acid phosphate, n-octyl acid phosphate, isodecyl acid phosphate , n-decyl acid phosphate, lauryl acid phosphate, myristyl acid phosphate, cetyl acid phosphate,
stearyl acid phosphate, docosyl acid phosphate, oleyl acid phosphate, 2-chloroethyl acid phosphate,
2,3-dipromo 2,3-dichloropropyl acid phosphate, dichloropropyl acid phosphate, cyclohexyl acid phosphate, phenyl acid phosphate, 0-tolyl acid phosphate, 2,3-xylyl acid phosphate Cydophosphate, P-cumenyl acid phosphate, mesityl acid phosphate, 1-naphthyl acid phosphate, 2-naphthyl acid phosphate, 1-anthryl acid phosphate, benzyl acid phosphate , phenethyl acid phosphate, styryl acid phosphate, cinnamyl acid phosphate, trityl acid phosphate, phenyl methyl phosphate, phenylethyl phosphate, phenyl n-propyl phosphate, phenyl n-butyl phosphate ate, phenyl n-octyl phosphate, phenyl lauryl phosphate, phenyl cyclohexyl phosphate, phenyl (2,3-xylyl) phosphate, cyclohexyl stearyl phosphate, cyclohexyl cetyl phosphate, dimethyl phosphate,
Diethyl phosphate, di-n-propyl phosphate, di-n-butyl phosphate, di-n-hexyl phosphate, di(2-ethylhexyl) phosphate, di-n-decyl phosphate, dilauryl phosphate, dimyristyl phosphate, Dicetyl phosphate, distearyl phosphate, dibehenyl phosphate, diphenyl phosphate, dicyclohexyl phosphate, di0-
Tolyl phosphate, bis(diphenylmethyl)
Examples include phosphate, bis(triphenylmethyl) phosphate, di(2,3-xylyl) phosphate, dibenzyl phosphate, di(1-naphthyl) phosphate, and the like. As metal salts of acidic phosphate ester compounds,
The above compounds sodium, potassium, lithium,
Calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin,
There are metal salts of metals such as copper, iron, vanadium, titanium, lead, and monobdenum. Examples of triazole compounds include 1,2,3-triazole, 4(5)-hydroxy-1,2,3-triazole, 5(6)-methyl-1,2,3-benzotriazole, 5-chloro-1, 2,3-benzotriazole, 7-nitro-1,2,3-benzotriazole, 4-benzoylamino-1,2,
3-benzotriazole, 4-hydroxy-1,
2,3-benzotriazole, naphtho-1,2,
3-triazole, 5,5-bis(1,2,3-
benzotriazole), 1,2,3-benzotriazole-4-sulfooctylamide, and the like. Specific examples of halohydrin and its derivatives are shown below. 2,2,2-trichloroethanol, 2,2,
2-tribromoethanol, 2,2,2-trifluoroethanol, 1,1,1-trichloro-2
-Methyl-2-propanol, 1,1,1-tribromo-2-methyl-2-propanol, 4,
4,4-tribromobutanol, 1,3-dibromo-2-propanol, 2,3-dibromo-1-
Propanol, 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol,
2,2-bis(bromomethyl)-3-bromo-1
-propanol, 2,2-bis(chloromethyl)
-3-chloro-1-propanol, 2,2-bis(bromomethyl)-1,3-propanediol,
2,2-bis(chloromethyl)-1,3-brondiol, 2,2-bis(fluoromethyl)-1,
3-Propanediol, N-phenyl-N-(1
-hydroxy-2,2,2-trichloroethyl)
Thiourea, N-(1-hydroxy-2,2,2-
trichloroethyl)-thiobenzamide, N-(1
-hydroxy-2,2,2-tribromoethyl)
-thioacetamide, 3-(N-1-hydroxy-2,2,2-trichloroethyl)aminopyridine, 4-(2-hydroxy-3,3,3-trichloropropyl)pyridine, 2-(1-hydroxy- 2,2,2-trichloroethyl)furan, N-
3-pyridyl-N-(1-hydroxy, 2,2,
2-trichloroethyl)urea, etc. Next, component (c) will be described. Nitrile compounds include acetonitrile, propionitrile, butyronitrile, valeronitrile, capronitrile, enantonitrile, caprylonitrile, pelargonitrile, caprinitrile, lauronitrile, palmitonitrile, stearonitrile, acronitrile, crotonitrile, malonitrile, Succinonitrile, glutaronitrile, adiponitrile, benzonitrile,
Examples include tolnitrile, benzyl cyanide, cinnamate nitrile, naphthonitrile, and cyanopyridine. Furthermore, as an additive for finely adjusting the color change temperature,
The following compounds may be added. Alcohols include monohydric alcohols, polyhydric alcohols, and derivatives thereof. Examples of these compounds are shown below. n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-lauryl alcohol, n-myristyl alcohol, n-cetyl alcohol, n-stearyl alcohol, n-icosyl alcohol, n-docosyl alcohol, n-
-mericyl alcohol, isocetyl alcohol,
Isostearyl alcohol, isodocosyl alcohol, oleyl alcohol, cyclohexanol, cyclopentanol, benzyl alcohol,
Cinnamyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol,
Examples include polyethylene glycol, propylene glycol, butylene glycol, hexylene glycol, cyclohexane-1,4-diol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, sorbitol, mannitol, and the like. Examples of compounds as esters are shown below. Amyl acetate, octyl acetate, butyl propionate, octyl propionate, phenyl propionate, ethyl caproate, amyl caproate, ethyl caprylate, amyl caprylate, ethyl caprate, amyl caprate, octyl caprate,
Methyl laurate, ethyl laurate, butyl laurate, hexyl laurate, octyl laurate, dodecyl laurate, myristyl laurate, cetyl laurate, stearyl laurate,
Methyl myristate, ethyl myristate, butyl myristate, hexyl myristate, octyl myristate, lauryl myristate, myristyl myristate, cetyl myristate, stearyl myristate, methyl palmitate, ethyl palmitate, butyl palmitate, palmitic acid Hexyl, octyl palmitate, lauryl palmitate, myristyl palmitate, cetyl palmitate, stearyl palmitate, methyl stearate, ethyl stearate, butyl stearate, hexyl stearate, octyl stearate, lauryl stearate, myristyl stearate, Cetyl stearate, stearyl stearate, methyl behenate, ethyl behenate, propyl behenate, butyl behenate, ethyl benzoate, butyl benzoate, amyl benzoate, phenyl benzoate, ethyl acetoacetate, methyl oleate, oleic acid Butyl, butyl acrylate, diethyl oxalate, dibutyl oxalate, diethyl malonate, dibutyl malonate, dibutyl tartrate, dibutyl sebatate, dimethyl sebatate, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, dibutyl fumarate, malein Examples include diethyl acid, dibutyl maleate, triethyl citrate, 12-hydroxystearic acid triglyceride, castor oil, dioxystearic acid methyl ester, and 12-hydroxystearic acid methyl ester. The following compounds are exemplified as ketones. Diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide, cyclohexanone, methylcyclohexanone, acetophenone, propiophenone, benzophenone, 2,4
- Pentanedione, acetonyl acetone, diacetone alcohol, ketone wax, etc. The following compounds are exemplified as ethers. Butyl ether, hexyl ether, diisopropyl benzyl ether, diphenyl ether,
Examples include dioxane, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol diphenyl ether, and ethylene glycol monophenyl ether. Examples of acid amide compounds are shown below. Acetamide, propionic acid amide, butyric acid amide, caproic acid amide, caprylic acid amide, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, benzamide , caproic acid anilide, caprylic acid anilide, capric acid anilide,
Lauric acid anilide, myristic acid anilide, palmitic acid anilide, stearic acid anilide, behenic acid anilide, oleic acid anilide, erucic acid anilide, caproic acid anilide, caprylic acid anilide, capric acid anilide, lauric acid anilide Methylamide, myristic acid N-methylamide, palmitic acid N-methylamide, stearic acid N-methylamide, behenic acid N-methylamide, oleic acid N-methylamide, erucic acid N-methylamide, lauric acid N-methylamide
-Ethylamide, myristic acid N-ethylamide, palmitic acid N-ethylamide, stearic acid N-ethylamide, oleic acid N-ethylamide, lauric acid N-butylamide, myristic acid N-butylamide, palmitic acid N-butylamide, stearic acid N-butylamide , oleic acid N-butylamide, lauric acid N-octylamide, myristic acid N-octylamide, palmitic acid N-octylamide, stearic acid N-octylamide, octylic acid N-octylamide, lauric acid N-dodecylamide, myristic acid acid N-
dodecylamide, palmitic acid N-dodecylamide, stearic acid N-dodecylamide, oleic acid N-dodecylamide, distearic acid amide,
Dipalmitic acid amide, Dimyristic acid amide,
dilauric acid amide, dioleic acid amide, tristearic acid amide, tripalmitic acid amide,
trimyristic acid amide, trilauric acid amide, trioleic acid amide, succinic acid amide, adipic acid amide, glutaric acid amide, malonic acid amide, azelaic acid amide, maleic acid amide,
Succinic acid N-methylamide, adipic acid N-methylamide, glutaric acid N-methylamide, malonic acid N-methylamide, azelaic acid N-methylamide, succinic acid N-ethylamide, adipic acid N-methylamide
-ethylamide, glutaric acid N, ethylamide,
Malonic acid N-ethylamide, azelaic acid N-ethylamide, succinic acid N-butylamide, adipic acid N-butylamide, glutaric acid N-butylamide, malonic acid N-butylamide, adipic acid N-butylamide
-octylamide, adipic acid N-dodecylamide, etc. Aliphatic carboxylic acids having 6 or more carbon atoms include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melisic acid. , isomyristic acid, isopalmitic acid, isostearic acid,
Oleic acid, elaidic acid, linoleic acid, linolenic acid, eleostearic acid, arachidonic acid, 2-
Oxylauric acid, 2-oxymyristic acid, 2
-oxypalmitic acid, 2-oxystearic acid, 3-oxystearic acid, 12-hydroxystearic acid, ricinoleic acid, 2-bromurauric acid, 2-bromyristic acid, 2-brompalmitic acid, 2-bromostearic acid, 18-bromstearic acid, 2-chlorostearic acid, 18-chlorostearic acid, dioxypalmitic acid, dioxystearic acid, 3-ethyl-3-lauryl-3
Oxypropionic acid, 2-methyl-3-oxystearic acid, 2-ketostearic acid, 2-ketopalmitic acid, azelaic acid monoethyl ester,
Azelaic acid monobutyl ester, azelaic acid monooctyl ester, sebacic acid monoethyl ester, sebacic acid monobutyl ester, sebacic acid monooctyl ester, sebacic acid monolauryl ester, 1,12-dodecamethylenedicarboxylic acid, 1,14-tetra decamethylene dicarboxylic acid, 1,16-hexadecamethylene dicarboxylic acid,
There are dimer acids, etc. Examples of thiol compounds are shown below. n-decyl mercaptan, n-dodecyl mercaptan, n-myristyl mercaptan, n-cetyl mercaptan, n-stearyl mercaptan,
Examples include iso-dodecyl mercaptan, iso-myristyl mercaptan, iso-cetyl mercaptan, and dodecylbenzyl mercaptan. Examples of sulfide compounds are shown below. Di-n-octyl sulfide, di-n-nonyl sulfide, di-n-decyl sulfide, di-n
-Dodecyl sulfide, di-n-myristyl sulfide, di-n-cetyl sulfide, di-n-stearyl sulfide, di-tert-dodecyl sulfide, octyldodecyl sulfide, diphenyl sulfide , dibenzyl sulfide, ditolyl sulfide, diethyl phenyl sulfide, 4,4
-Dichlorodiphenyl sulfide, dilaurylthiodipropionate, distearylthiodipropionate, tetra(laurylthiopropionic acid)
Examples include pentaerythritol ester and tetra(stearylthiopropionic acid) pentaerythritol. Examples of disulfide compounds are shown below. Di-n-decyl disulfide, di-n-dodecyl disulfide, di-n-myristyl disulfide, di-n-cetyl disulfide, di-n-stearyl disulfide, diphenyl disulfide ,
Examples include dibenzyl disulfide, ditolyl disulfide, dinaphthyl disulfide, and 4,4-dichlorodiphenyl disulfide. Examples of sulfoxide compounds are shown below. Examples include dimethyl sulfoxide, diethyl sulfoxide, tetramethylene sulfoxide, diphenyl sulfoxide, and dibenzyl sulfoxide. Examples of sulfone compounds are shown below. Examples include diethyl sulfone, dibutyl sulfone, methyl phenyl sulfone, diphenyl sulfone, ditolyl sulfone, dibutyl phenyl sulfone, dibenzyl sulfone, 4,4-dichlorodiphenyl sulfone, and the like. The weight ratio of the above three components (a), (b) and (c) is 1:0.1~
The reversible thermochromic material of the present invention can be obtained by mixing and melting in a ratio of 20:1 to 200, preferably 1:1 to 10:10 to 100, to obtain a homogeneous composition. Here, component (a) determines the color of the thermochromic material, component (b) reacts with component (a) to cause reversible coloring, and component (ha) ) determines the temperature at which the reaction occurs (color change temperature) and plays a role in controlling its sensitivity. These thermochromic materials may be solid or liquid at room temperature, but they are liquid at temperatures above their respective color change points, such as strong acidic substances that irreversibly color component (a), and component (a) and (a). If it comes into contact with other substances, such as substances that interfere with the reaction (b), its properties may be impaired. By using the well-known microencapsulation method, the above-mentioned problem can be solved by forming microcapsules with particle diameters of several to about 30 μm that encapsulate the thermochromic material. It is also possible to coexist with a thermochromic material that indicates temperature, expanding its uses. A specific example will be explained below. Table 1 shows the composition, color change temperature, and color change of each example. The numbers in parentheses are the composition ratios expressed in parts by weight, and the color change temperature is expressed at 0°C.The color change is shown on the left side of the arrow when it is lower than the color change temperature, and on the right side is the color when it is higher than the color change temperature. did. Examples 10 and 11 are examples of thermochromic materials encapsulated in microcapsules. Explanation of symbols in the table CVL: Crystal violet lactone leuco dye A: Spiro[12-H-benzo[ ]xanthene-12,1(3H)-isobenzofuran]-3-one, 9-(diethylamino)-leuco dye B: Spiro [isobenzofuran-1
(3H), 9-[9H]xanthene]-3-
1, 2-chloro-6-(diethylamino)-3-methyl-leuco dye C: spiro[isobenzofuran-1
(3H), 9-[9H]xanthene]-3-
on, 6-diethylamino-3-methyl-2-(phenylamino)-leuco dye D: Spiro[isobenzofuran-1
(3H), 9-[9H]xanthene]-3-
on, 6-(diethylamino)-2-
[Cyclohexyl (phenylmethyl)
Amino〕-

[Table] Example 10 80 g of the thermochromic material of the example heated to 80°C is added dropwise into 30 g of a 5% aqueous gelatin solution, and stirred to form fine droplets. Additionally, 80g of 5% gum arabic solution
was added, the pH of the system was adjusted to 5 by adding acetic acid under stirring, and 200 g of water was added to cause coacervation. The pH is then lowered to 4.4, followed by the addition of 1 g of 87% formalin for membrane crosslinking. In the previous operations, the liquid temperature was kept at 50℃. Next, in order to gel the thick liquid film, the system was cooled to 10°C, the pH was adjusted to 9, and after being left for several hours, centrifugation and water washing were performed to obtain microcapsules containing a thermochromic material. This thermochromic material in the form of microcapsules exhibited exactly the same color changing characteristics as the thermochromic material encapsulated therein. Example 11 5 g of Epicoat to 80 g of the thermochromic material of Example
Dissolve 828 (epoxy resin manufactured by Shell Oil Co., Ltd.) by heating at 80°C, drop it into 150 g of a 5% aqueous gelatin solution, and stir to form fine droplets. Separately, dissolve 3g of curing agent (amine adduct of epoxy resin manufactured by Shell Oil Co., Ltd.) in 20g of water, gradually add this to the previously stirred solution, and keep the liquid temperature at 80°C for about 4 hours. Continue stirring. After being left to cool, it was centrifuged and washed with water to obtain microcapsules containing a thermochromic material. This thermochromic material in the form of microcapsules exhibited exactly the same color changing characteristics as the thermochromic material encapsulated therein. The thermochromic material of the present invention is used as a printing ink or paint by being dispersed in a vehicle, or as a molded body or filament by being kneaded into a polymer as a temperature indicating material that changes color due to temperature changes, or as an indicating material for appropriate temperature or dangerous temperature. It is also used to enjoy the surface color, design, etc. that changes with temperature changes.

Claims (1)

[Scope of Claims] 1 (a) Electron-donating color-forming organic compounds, (b) Compounds having a phenolic hydroxyl group and metal salts thereof, aromatic carboxylic acids, aliphatic carboxylic acids having 2 to 5 carbon atoms, and the like. one or more compounds selected from metal salts of, acidic phosphoric acid esters and metal salts thereof, 1,2,3-triazoles and derivatives thereof, halohydrins having 2 to 5 carbon atoms and derivatives thereof, and (iii) nitrile. A reversible thermochromic material consisting of a composition containing three compounds as essential components. 2. The reversible thermochromic material according to claim 1, which is encapsulated in microcapsules.